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Key Finder: Which Key Fits My Notes?

This key finder shows you the key of a piece: click the notes that appear in it and you see every major and minor key that contains all of them, together with the key signature and the scale.

Source: C. L. Krumhansl: Cognitive Foundations of Musical Pitch. Oxford University Press 1990 (key profiles after Krumhansl & Kessler 1982, Table 2.1; key estimation after Krumhansl-Schmuckler, Chapter 4). Updated: .

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One audio file (MP3, M4A, WAV, OGG, FLAC …), up to 60 minutes

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Key of the recording

Choose an audio file – the estimated key appears here.

e.g. Am F C G. If chords are entered, their notes count instead of the checkboxes.
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Result

Matching keys
3 keys fit: C major / A minor · G major / E minor · F major / D minor
Keys at a glance
Key (major / relative minor)Key signatureCamelotNotes of the major scale
C major / A minorno accidentals8B / 8AC D E F G A B
G major / E minor1 ♯9B / 9AG A B C D E F♯
F major / D minor1 ♭7B / 7AF G A B♭ C D E
Notes
  • Selected notes (5): C, D, E, G, A
  • A major key and its relative minor share the same notes. The tonic usually tells you which one is meant: the piece starts or ends on it, and the final chord is major or minor.
Minor is treated as natural minor here. The key pairs with F♯ and G♭ (six accidentals each) are enharmonically equal.

How it is calculated

The key is the scale a piece’s notes come from: mark the notes that occur and the tool lists every matching major and minor pair. The key signature shows which notes are raised or lowered.

How the key is found

Every major scale uses seven of the twelve semitones. Its relative minor uses exactly the same notes and therefore has the same key signature. The tool checks all 13 key signatures to see whether your selected notes are fully contained. The fewer notes you select, the more keys fit; the more you select, the clearer the result becomes.

Major or minor?

The notes alone do not tell you. Listen for the tonic: if the piece ends on C and sounds bright, it is C major; if it ends on A and sounds darker, it is A minor.

Key from an audio file

Drop in an audio file: it is read in your browser only and never uploaded. The tool measures how strongly each of the twelve pitch classes occurs (chroma) and compares that pattern with the Krumhansl-Schmuckler key profiles for all 24 major and minor keys. You see the best match, the Camelot code used by DJs (C major = 8B, A minor = 8A), the relative key, other possible keys, a confidence level and the tuning of the recording relative to A4 = 440 Hz.

This is an estimate. A major key and its relative minor share all notes and are confused most often; tracks that change key or consist mostly of drums or speech give uncertain results. At most the first 4 minutes are analysed.

Key from chords

Enter a progression such as Am F C G in the “Chords” field: its notes are A, C, E, F, G, B and D – exactly the notes of C major and A minor, so that key is shown. The table also gives the Camelot number for every key.

Frequently asked questions

How do I find the key of a song?

Collect all the notes that occur and look up which scale contains them all. Then decide between major and minor by the tonic and the final chord.

How can I tell major from minor?

Major usually sounds brighter, minor darker. The tonic decides: the piece starts or ends on it, and the triad on it has a major or a minor third.

Why are several keys shown?

Because different scales can contain the same notes. C major and A minor, for example, have exactly the same seven notes.

What do foreign notes in the result mean?

They are selected notes that do not belong to the key, for example because of a modulation or a leading tone in harmonic minor.

Sources and legal basis

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